Two Kohala Coast legends with Hawaii's cleanest beach water
Beach: Kaunaʻoa Bay (Mauna Kea Beach)
Kauna'oa Bay at the Mauna Kea is one of the cleanest beaches in Hawaii. The dry Kohala Coast receives minimal rainfall, has no stream outlets, and the bay's crescent shape provides excellent ocean flushing. Very low bacteria risk.
Beach: Mauna Lani Beach
Mauna Lani's beaches share the Kohala Coast's excellent water quality. The arid climate (less than 10 inches of rain per year in some areas) means virtually no runoff. Ancient fishponds and lava-rock coastline add to the experience.
Both resorts share the Kohala Coast's exceptional water quality — among the cleanest beach water in all of Hawaii. The dry leeward coast of the Big Island receives minimal rainfall (some areas under 10 inches per year), producing virtually zero runoff. There are no streams, canals, or cesspools affecting either beach. The main difference is beach character: Mauna Kea's Kauna'oa Bay is a perfect crescent of white sand consistently rated Hawaii's best beach, while Mauna Lani offers a more varied coastline with historic fishponds and lava-rock features.
Water quality risk ratings are based on publicly available data from the Hawaii Department of Health Clean Water Branch, EPA impaired waters database, USGS stream monitoring data, and geographic analysis of pollution sources (streams, cesspools, storm drains). Ratings are estimates and may change with conditions.
Top-rated experiences near these hotels. Check water quality above, then plan your trip.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent project not affiliated with any hotel, resort, or the Hawaii DOH. Water quality ratings are estimates based on publicly available data — not real-time measurements.
Always verify conditions with the Hawaii DOH Clean Water Branch before swimming.
When in doubt, don't go out. 🤙